OBJECTIVES: To determine the prevalence of chronic conditions in managed care-enrolled Medicare seniors (age 65 plus) and to examine the association between self-reported chronic conditions and health status as measured by the SF-36. METHODS: Data were obtained from the 2001 Medicare Health Outcomes Survey (HOS). The HOS is conducted by the Centers for Medicare and Medicaid Services to assess the quality of care provided to Medicare beneficiaries enrolled in managed care. The survey questionnaire, which was administered by phone or mail, includes the SF-36 and items addressing demographic characteristics, depressive symptoms, and chronic conditions. The SF-36 is comprised of eight multi-item scales, four of which are considered "physical" domains and four are considered "mental" domains. For this analysis, number of chronic conditions and the prevalence of each condition were described. An ordinary least squares regression model was conducted for each SF-36 scale to estimate the association between each chronic condition and the scale scores after adjusting for demographic variables. RESULTS: More than 90% of respondents had at least one chronic condition. Among the chronic conditions, hypertension (57.6%), arthritis of the hip or knee (40.5%), and arthritis of the hand or wrist (34.1%) were the most commonly reported. Compared with other variables, age, arthritis, and depressive symptoms were highly associated with the SF-36 physical domains. Depressive symptoms had the strongest association with each of the four SF-36 mental domains. Among the chronic conditions, the adverse impact of having difficulty in controlling urination, a relatively neglected condition, was only second to depressive symptoms in its negative relationship with vitality, social-functioning, and mental health. CONCLUSION: Chronic conditions were commonly reported among the older adults. The unique associations found between chronic conditions and domains of health status demonstrate the importance of examining the burden of these conditions in terms of functioning and well-being.